1. Field of the Invention
The present invention generally relates to needles used in percutaneous diagnostic and therapeutic procedures, and more specifically to needles incorporating fiber-optic stylets which are provided to localize placement of the tip of the needle during surgical and medical diagnostic procedures.
2. Information Disclosure
In medical radiology, long, slender or skinny needles have been inserted into various body organs through the skin for a variety of purposes, e.g., to obtain tissue for biopsy from probable tumor masses such as from the lungs, kidneys, pancreas, or liver, to cannulate liver ducts by percutaneous transhepatic cholangiography, or to pierce the kidney pelvis in preparation for a percutaneous nephrostomy in order to treat blocked ureters.
Despite the use of preliminary measuring procedures such as ultrasound and CT scanning, and the use of fluoroscopy, it is extremely difficult, if not impossible, for a doctor or technician to determine the positional relationship of the tip of a needle to an internal organ or part of an organ to be treated. In the case of percutaneous transhepatic cholangiography, for example, a needle is inserted deep into a liver and is slowly retracted while small doses of contrast material are injected to determine whether the needle tip is properly positioned within the liver duct system. The needles used in these procedures have metal stylets, which fill the needle so that the needle is essentially solid as it traverses the body as it moves towards its final position. This prevents bits of tissue from entering the tube of the needle, and undesirably results in "blocked" needles.
NORTHEVED, U.S. Pat. No. 3,961,621, discloses a device capable of taking biological samples from a human body. The device comprises an elongated bevel-cut tubular needle, a tubular stiletto having a sharp edged distal end, a core of optical fibers, and bundles of light conducting fibers. The stiletto covers the fiber bundles, which are evenly distributed within a space located between a core of the device and the stiletto tube wall. Spaces between the fiber bundles serve as air ducts in order to create a partial vacuum which cause the sample collected to adhere to the distal end of the device. The fiber bundles guide light from an exterior source to an interior surface of the body, and the core of guiding light fibers reflect the light back to an external display unit. In order to collect a biological sample, a partial vacuum is applied to cause the stiletto to slide forwardly through the needle and into abutment with an interior surface of the body. The distal end of the stiletto cuts out a biological sample, which due to the vacuum applied adheres to the distal end of the needle.
MATSUO, U.S. Pat. No. 4,269,192, discloses a device for diagnosing illness. The device comprises a tubular member having a bevel-cut end, light guiding means, and a photosensitive device. The light guiding means are inserted into the tubular member, and both of the tip ends are bevel-cut to match the level that of the end portion caps of the tubular member. The end-portion caps are inserted into the examination area using the light guide in order to admit light into the examination area through the front end of the tip. Light is reflected from the examination area and then admitted into the light guide fiber through the front end, thus activating an LED by the photosensor. The intensity of light reflected and signalled by the LED indicates the exact location of the end-position caps of the member.
TAKAHASHI, U.S. Pat. No. 3,556,085, discloses an optical viewing device which comprises a bevel-cut fiber-optic system, a magnifying objective lens system, a fiber-optic viewing system, a magnifying eye piece, and an illuminating system. The device is inserted into a living body for direct examination of interior surfaces, and the tip of the fiber-optic system is inserted into a body and illuminated by the system. The magnifying system and an eyepiece are used to examine an area of interest, and the lens system can be variously positioned in order to obtain different types of magnification.
FOURESTIER, U.S. Pat. No. 2,432,294, discloses a lighting device for endoscopes which comprises a transparent rod having a plurality of reflective surfaces for guiding light to an interior region of a body to be observed. The transparent rod is contained within a sheath to guard against humidity, and a space is filled with dry air and separates the sheath from the rod. In cases where lateral illumination is desired, the sheath can be bevel-cut. The rod can also be bevel-cut, but need not extend to the tip of the sheath.
None of these patents, however, disclose the use of a reflective surface layer on a receiving optical fiber which is adapted to redirect incoming light back to a light sensor and an analyzer. The reflective layer increases the precision of the analysis which can be performed.